Model verification

[Sina.Ameli]

Dear Dr. Jonkman,

When I apply a zero input (pitch angel is zero) fpr test 24, I will get this error message:

An error occurred while running the simulation and the simulation was terminated
Caused by:
Error reported by S-function ‘FAST_SFunc’ in ‘PI2_FAST/FAST Nonlinear Wind Turbine/S-Function’:
FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates(node 6, blade 1):BEMT_UnCoupledSolve:DeterminePhiBounds:There is no valid value of phi for these operating conditions! Vx = -1.295, Vy = 34.21, rlocal = 15.852, theta = 0.20019

What is the cause of this error?
I also get an error of this :

an error occurred while running the simulation and the simulation was terminated
Caused by:
Error reported by S-function ‘FAST_SFunc’ in ‘PI2_FAST/FAST Nonlinear Wind Turbine/S-Function’:
FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates(node 7, blade 2):BEMT_UnCoupledSolve:DeterminePhiBounds:There is no valid value of phi for these operating conditions! Vx = 1.5908, Vy = -24.552, rlocal = 20.113, theta = 0.1497

When I apply a nominal pitch angel for test 18!

Besides, I implement a PI control and the input of the system is equilibrium point, but I get a very oscillatory response for Test 24 like this:

while I remember that Test 18 didn’t give me these much oscillations with a PI control in the operating point! I don’t understand why it is too much oscillatory with only a step wind?!

Thanks,
Best regards,
Sina

[Jason.Jonkman]

Dear Sina,

The error regarding “no valid value of phi” has been discussed many times on this forum was fixed in versions of AeroDyn v15 newer than FAST v8.16. I suggest that you upgrade from FAST v8.16 to OpenFAST: github.com/OpenFAST/openfast.

Regarding the large oscillations in response, I can’t really comment more without understanding more about your simulation settings.

Best regards,

[Sina.Ameli]

Dear Dr. Jonkman,
Thank for your reply. Actually, I have several questions.

1- Regarding the oscillations, you’re right. You cannot tell anything about the those oscillations without having detailed information. Let me ask my question in other word. Suppose I apply the control input (pitch) in an operating point, say 19.94 deg, and the exogenous input, say a step wind speed of Vx=22m/s, Vy=0; Vz=0, starting at the initial condition for the pitch angel exactly at the equilibrium point, i.e 19.94 deg, and the generator speed of 12.1 rpm, then the generator speed and the pitch angel for Test24 compared with the PI control (the one you exactly used in your documents for offshore WT) are as follows:

Both open loop and closed loop have the same initial conditions, and step wind speed.
As in the onshore WT the response settles, is these oscillations normal in the offshore WT with an step wind speed?
I did a little research and found a paper published recently. It shows the results of the pitch control (rotor speed tracking problem) for a 5 MW offshore WT in FAST. The responses settled very well.

2- I compared the primary input files of test 18 with 24. The flags “CompHydro”, and “CompMooring” are one in test 24, while for test 18 they are zero. Could you explain what are these physically and what are their effects on WT?

3- Is it possible to get output from blade pitch 2 and 3 in test 18? If so, how?

4- Regarding the OpenFAST, where are the “bin” and “source” files to set path in Matlab? I set path to D:\openfast-master\glue-codes\simulink\src, where the file “FAST_SFunc.c” is located in, and I downloaded the “windows_openfast_binaries” file separately and pasted it to the D:\openfast-master then set path to D:\openfast-master\windows_openfast_binaries\openfast_v2.2.0_binaries\DISCON_DLLS\64bit. When I run the OpenLoop Simulink file, Matlab gives still gives me the following error:
Error in S-function ‘OpenLoop/FAST Nonlinear Wind Turbine/S-Function’: S-Function ‘FAST_SFunc’ does not exist\

Besides, where are the primary and other input files for the 5MW offshore WT? Is there any organized documentation to be able to run the Simulink quickly?

Thanks,
Best regards,
Sina

[Jason.Jonkman]

Dear Sina,

Here are my answers to your questions:

1. In your plots, it doesn’t look like the rotor speed is initialized to 12.1 rpm because (1) the generator speed (=rotor speed*97 for the NREL 5-MW turbine) starts well below 1173.7 rpm in your plots and (2) the blade-pitch angle drops suddenly at time zero when control is enabled. Other than that, I’m not sure I can comment more because I’m not sure what controller you’ve enabled.

2. Test18 is for a land-based NREL 5-MW baseline turbine, which does not have hydrodynamic loads on the substructure nor does it have a mooring system, so HydroDyn and a mooring module are disabled for this simulation. Test24 is a model of the OC3-Hywind spar, which has HydroDyn and MAP++ enabled.

3. Yes, but without modification, the pitch controller in Test18 uses collective pitch, so, the pitch angle of all blades should be the same. Regardless, pitch angles may be output from the ElastoDyn module (that is, include BldPitch1, BldPitch2, and BldPitch3 in the OutList of the ElastoDyn input file).

4. The compiled OpenFAST S-Function does not appear to be included in the “windows_openfast_binaries.zip” file. You’ll have to compile the OpenFAST S-Function before using the Simulink-OpenFAST interface. This interface is very similar to the one for FAST v8, which is documented in the FAST v8 ReadMe file: github.com/OpenFAST/r-test.

Best regards,

[Sina.Ameli]

Dear Dr. Jonkman,

Thanks for replying to all of my question. Please see the following results for the rotor speed and control signal:

The initial conditions are the operating condition (wind speed=22m/s, pitch=19.94 deg, rotor speed=1.267rad/s, Test 24). I used a simple PI control and a just add a bias term to the PI, which is exactly 19.94 deg. I wonder why the rotor speed has a lot of oscillations? (No matter what are the PI gains are, although it tracks near the rated rotor speed value, it always has a lot of oscillations and never settled while I apply rated values in the steady state situations). The problem is that in the open loop, the rotor speed cannot stay in the equilibrium point and has oscillations! As you mentioned that I don’t know what is happening at the beginning that pitch angle is suddenly becomes zero then goes to its steady state situation.

Thanks,
Best regards,
Sina

[Jason.Jonkman]

Dear Sina,

I’m not sure I can comment as the response seems to be driven by your controller, which it sounds like you’ve implemented yourself. Can you clarify how you are applying pitch control and torque control?

Best regards,

[Sina.Ameli]

Dear Dr. Jonkman,
Thanks for your reply. Actually, it is a simple PI control with a bias term that is exactly equal to the pitch angle at the operating point. However, let’s get back to your PI control. Why is it settled very well for test 18 but not for test 24?

The PI control in your document is for an offshore WT but it seems work well for an onshore WT! Is it because an onshore wind turbine’s dynamics is different from offshore WTs, for example because of hydrodynamics and mooring system?

[Jason.Jonkman]

Dear Sina,

There are two reasons for this difference:

• The offshore systems has different dynamics (including low-frequency platform motions) than the land-based system.
• Because of these lower frequencies, the gains in the blade-pitch controller for the offshore system were reduced relative to those from the land-based system. This is documented more in the OC3-Hywind spar specifications report: nrel.gov/docs/fy10osti/47535.pdf

Best regards,

[Sina.Ameli]

Dear Dr. Jonkman,

Thank you so much for sending me the document for the offshore WT. I reduced the gains, then oscillations seem reduced a little like this:

Thanks,
Best regards,
Sina

[Sina.Ameli]

Dear Dr. Jonkman,

I have another question. Recently, I have read a paper implementing a controller (pitch control) on a 5MW offshore WT and shows the following results:

Now, I am confused. While I cannot get a settled response with NREL’s PI control due to hydrodynamics, and mooring system, this paper shows a completely settled responses!
Besides, you told me that the three blade pitch angles are different for TEST 24 (offshore), while they are the same (collective) for Test 18 (onshore). Why are the above figures for the pitch angles the same if it is an offshore WT?!

Thanks,
Best regards,
Sina

[Jason.Jonkman]

Dear Sina

The baseline controller used in Tests 18 and 24 are nearly identical, just with different gains. Both are for collective blade-pitch control, so, the pitch angles are the same between the three blades for both tests.

I don’t think I can really comment on the plots you are showing because I don’t know their source. And the response, of course, will depend on the type of offshore wind turbine (and corresponding natural frequencies), as well as the controller used. The NREL 5-MW baseline controller is just that–a baseline–and I’m sure changes to the controller can be made to improve its performance. But in steady conditions, the baseline controller will settle out to a constant value after the transients die out; for the floating OC3-Hywind system this will take a while due to the very low natural frequencies of the platform in surge and pitch.

Best regards,

[Sina.Ameli]

Dear Dr. Jonkman,

Thanks, I really appreciate that you replied to my questions promptly at all time.

Best regards,
Sina

[NingXiang.Gao]

Hello all,
I am new to this forum and a beginner to FAST. I built an 8 DOF onshore wind turbine model based on Lagrange equation and wanted to verify it with FAST. Over time, the in-plane displacement and out-plane displacement should tend to sinusoidal waveform.But I can’t run it.My question is wider and I’m sorry for that. I would like to know, with your experience, what could cause this problem?
This is my input file.
------- FAST v8.16.* INPUT FILE ------------------------------------------------
FAST Certification Test #18: NREL 5.0 MW Baseline Wind Turbine (Onshore)
---------------------- SIMULATION CONTROL --------------------------------------
false Echo - Echo input data to .ech (flag)
“FATAL” AbortLevel - Error level when simulation should abort (string) {“WARNING”, “SEVERE”, “FATAL”}
120 TMax - Total run time (s)
0.00625 DT - Recommended module time step (s)
2 InterpOrder - Interpolation order for input/output time history (-) {1=linear, 2=quadratic}
0 NumCrctn - Number of correction iterations (-) {0=explicit calculation, i.e., no corrections}
99999 DT_UJac - Time between calls to get Jacobians (s)
1E+06 UJacSclFact - Scaling factor used in Jacobians (-)
---------------------- FEATURE SWITCHES AND FLAGS ------------------------------
1 CompElast - Compute structural dynamics (switch) {1=ElastoDyn; 2=ElastoDyn + BeamDyn for blades}
1 CompInflow - Compute inflow wind velocities (switch) {0=still air; 1=InflowWind; 2=external from OpenFOAM}
2 CompAero - Compute aerodynamic loads (switch) {0=None; 1=AeroDyn v14; 2=AeroDyn v15}
0 CompServo - Compute control and electrical-drive dynamics (switch) {0=None; 1=ServoDyn}
0 CompHydro - Compute hydrodynamic loads (switch) {0=None; 1=HydroDyn}
0 CompSub - Compute sub-structural dynamics (switch) {0=None; 1=SubDyn}
0 CompMooring - Compute mooring system (switch) {0=None; 1=MAP++; 2=FEAMooring; 3=MoorDyn; 4=OrcaFlex}
0 CompIce - Compute ice loads (switch) {0=None; 1=IceFloe; 2=IceDyn}
---------------------- INPUT FILES ---------------------------------------------
“5MW_Baseline/NRELOffshrBsline5MW_Onshore_ElastoDyn.dat” EDFile - Name of file containing ElastoDyn input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(1) - Name of file containing BeamDyn input parameters for blade 1 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(2) - Name of file containing BeamDyn input parameters for blade 2 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_BeamDyn.dat” BDBldFile(3) - Name of file containing BeamDyn input parameters for blade 3 (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_InflowWind_12mps.dat” InflowFile - Name of file containing inflow wind input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_Onshore_AeroDyn15.dat” AeroFile - Name of file containing aerodynamic input parameters (quoted string)
“5MW_Baseline/NRELOffshrBsline5MW_Onshore_ServoDyn.dat” ServoFile - Name of file containing control and electrical-drive input parameters (quoted string)
“unused” HydroFile - Name of file containing hydrodynamic input parameters (quoted string)
“unused” SubFile - Name of file containing sub-structural input parameters (quoted string)
“unused” MooringFile - Name of file containing mooring system input parameters (quoted string)
“unused” IceFile - Name of file containing ice input parameters (quoted string)
---------------------- OUTPUT --------------------------------------------------
True SumPrint - Print summary data to “.sum” (flag)
5 SttsTime - Amount of time between screen status messages (s)
99999 ChkptTime - Amount of time between creating checkpoint files for potential restart (s)
“default” DT_Out - Time step for tabular output (s) (or “default”)
0 TStart - Time to begin tabular output (s)
2 OutFileFmt - Format for tabular (time-marching) output file (switch) {1: text file [.out], 2: binary file [.outb], 3: both}
True TabDelim - Use tab delimiters in text tabular output file? (flag) {uses spaces if false}
“ES10.3E2” OutFmt - Format used for text tabular output, excluding the time channel. Resulting field should be 10 characters. (quoted string)
---------------------- LINEARIZATION -------------------------------------------
False Linearize - Linearization analysis (flag)
2 NLinTimes - Number of times to linearize (-) [>=1] [unused if Linearize=False]
30, 60 LinTimes - List of times at which to linearize (s) [1 to NLinTimes] [unused if Linearize=False]
1 LinInputs - Inputs included in linearization (switch) {0=none; 1=standard; 2=all module inputs (debug)} [unused if Linearize=False]
1 LinOutputs - Outputs included in linearization (switch) {0=none; 1=from OutList(s); 2=all module outputs (debug)} [unused if Linearize=False]
False LinOutJac - Include full Jacobians in linearization output (for debug) (flag) [unused if Linearize=False; used only if LinInputs=LinOutputs=2]
False LinOutMod - Write module-level linearization output files in addition to output for full system? (flag) [unused if Linearize=False]
---------------------- VISUALIZATION ------------------------------------------
0 WrVTK - VTK visualization data output: (switch) {0=none; 1=initialization data only; 2=animation}
1 VTK_type - Type of VTK visualization data: (switch) {1=surfaces; 2=basic meshes (lines/points); 3=all meshes (debug)} [unused if WrVTK=0]
true VTK_fields - Write mesh fields to VTK data files? (flag) {true/false} [unused if WrVTK=0]
15 VTK_fps - Frame rate for VTK output (frames per second){will use closest integer multiple of DT} [used only if WrVTK=2]

------- ELASTODYN V1.00.* INDIVIDUAL BLADE INPUT FILE --------------------------
NREL 5.0 MW offshore baseline blade input properties.
---------------------- BLADE PARAMETERS ----------------------------------------
49 NBlInpSt - Number of blade input stations (-)
0.477465 BldFlDmp(1) - Blade flap mode #1 structural damping in percent of critical (%)
0.477465 BldFlDmp(2) - Blade flap mode #2 structural damping in percent of critical (%)
0.477465 BldEdDmp(1) - Blade edge mode #1 structural damping in percent of critical (%)
---------------------- BLADE ADJUSTMENT FACTORS --------------------------------
1 FlStTunr(1) - Blade flapwise modal stiffness tuner, 1st mode (-)
1 FlStTunr(2) - Blade flapwise modal stiffness tuner, 2nd mode (-)
1.057344 AdjBlMs - Factor to adjust blade mass density (-) !bjj: value for AD14=1.04536; value for AD15=1.057344 (it would be nice to enter the requested blade mass instead of a factor here)
1 AdjFlSt - Factor to adjust blade flap stiffness (-)
1 AdjEdSt - Factor to adjust blade edge stiffness (-)

------- ELASTODYN v1.03.* INPUT FILE -------------------------------------------
NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis. Properties from Dutch Offshore Wind Energy Converter (DOWEC) 6MW Pre-Design (10046_009.pdf) and REpower 5M 5MW (5m_uk.pdf)
---------------------- SIMULATION CONTROL --------------------------------------
False Echo - Echo input data to “.ech” (flag)
3 Method - Integration method: {1: RK4, 2: AB4, or 3: ABM4} (-)
“DEFAULT” DT - Integration time step (s)
---------------------- ENVIRONMENTAL CONDITION ---------------------------------
9.80665 Gravity - Gravitational acceleration (m/s^2)
---------------------- DEGREES OF FREEDOM --------------------------------------
True FlapDOF1 - First flapwise blade mode DOF (flag)
False FlapDOF2 - Second flapwise blade mode DOF (flag)
True EdgeDOF - First edgewise blade mode DOF (flag)
False TeetDOF - Rotor-teeter DOF (flag) [unused for 3 blades]
False DrTrDOF - Drivetrain rotational-flexibility DOF (flag)
False GenDOF - Generator DOF (flag)
False YawDOF - Yaw DOF (flag)
True TwFADOF1 - First fore-aft tower bending-mode DOF (flag)
False TwFADOF2 - Second fore-aft tower bending-mode DOF (flag)
True TwSSDOF1 - First side-to-side tower bending-mode DOF (flag)
False TwSSDOF2 - Second side-to-side tower bending-mode DOF (flag)
False PtfmSgDOF - Platform horizontal surge translation DOF (flag)
False PtfmSwDOF - Platform horizontal sway translation DOF (flag)
False PtfmHvDOF - Platform vertical heave translation DOF (flag)
False PtfmRDOF - Platform roll tilt rotation DOF (flag)
False PtfmPDOF - Platform pitch tilt rotation DOF (flag)
False PtfmYDOF - Platform yaw rotation DOF (flag)
---------------------- INITIAL CONDITIONS --------------------------------------
0 OoPDefl - Initial out-of-plane blade-tip displacement (meters)
0 IPDefl - Initial in-plane blade-tip deflection (meters)
0 BlPitch(1) - Blade 1 initial pitch (degrees)
0 BlPitch(2) - Blade 2 initial pitch (degrees)
0 BlPitch(3) - Blade 3 initial pitch (degrees) [unused for 2 blades]
0 TeetDefl - Initial or fixed teeter angle (degrees) [unused for 3 blades]
0 Azimuth - Initial azimuth angle for blade 1 (degrees)
12.1 RotSpeed - Initial or fixed rotor speed (rpm)
0 NacYaw - Initial or fixed nacelle-yaw angle (degrees)
0 TTDspFA - Initial fore-aft tower-top displacement (meters)
0 TTDspSS - Initial side-to-side tower-top displacement (meters)
0 PtfmSurge - Initial or fixed horizontal surge translational displacement of platform (meters)
0 PtfmSway - Initial or fixed horizontal sway translational displacement of platform (meters)
0 PtfmHeave - Initial or fixed vertical heave translational displacement of platform (meters)
0 PtfmRoll - Initial or fixed roll tilt rotational displacement of platform (degrees)
0 PtfmPitch - Initial or fixed pitch tilt rotational displacement of platform (degrees)
0 PtfmYaw - Initial or fixed yaw rotational displacement of platform (degrees)
---------------------- TURBINE CONFIGURATION -----------------------------------
3 NumBl - Number of blades (-)
63 TipRad - The distance from the rotor apex to the blade tip (meters)
1.5 HubRad - The distance from the rotor apex to the blade root (meters)
-2.5 PreCone(1) - Blade 1 cone angle (degrees)
-2.5 PreCone(2) - Blade 2 cone angle (degrees)
-2.5 PreCone(3) - Blade 3 cone angle (degrees) [unused for 2 blades]
0 HubCM - Distance from rotor apex to hub mass [positive downwind] (meters)
0 UndSling - Undersling length [distance from teeter pin to the rotor apex] (meters) [unused for 3 blades]
0 Delta3 - Delta-3 angle for teetering rotors (degrees) [unused for 3 blades]
0 AzimB1Up - Azimuth value to use for I/O when blade 1 points up (degrees)
-5.0191 OverHang - Distance from yaw axis to rotor apex [3 blades] or teeter pin [2 blades] (meters)
1.912 ShftGagL - Distance from rotor apex [3 blades] or teeter pin [2 blades] to shaft strain gages [positive for upwind rotors] (meters)
-5 ShftTilt - Rotor shaft tilt angle (degrees)
1.9 NacCMxn - Downwind distance from the tower-top to the nacelle CM (meters)
0 NacCMyn - Lateral distance from the tower-top to the nacelle CM (meters)
1.75 NacCMzn - Vertical distance from the tower-top to the nacelle CM (meters)
-3.09528 NcIMUxn - Downwind distance from the tower-top to the nacelle IMU (meters)
0 NcIMUyn - Lateral distance from the tower-top to the nacelle IMU (meters)
2.23336 NcIMUzn - Vertical distance from the tower-top to the nacelle IMU (meters)
1.96256 Twr2Shft - Vertical distance from the tower-top to the rotor shaft (meters)
87.6 TowerHt - Height of tower above ground level [onshore] or MSL [offshore] (meters)
0 TowerBsHt - Height of tower base above ground level [onshore] or MSL [offshore] (meters)
0 PtfmCMxt - Downwind distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMyt - Lateral distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmCMzt - Vertical distance from the ground level [onshore] or MSL [offshore] to the platform CM (meters)
0 PtfmRefzt - Vertical distance from the ground level [onshore] or MSL [offshore] to the platform reference point (meters)
---------------------- MASS AND INERTIA ----------------------------------------
0 TipMass(1) - Tip-brake mass, blade 1 (kg)
0 TipMass(2) - Tip-brake mass, blade 2 (kg)
0 TipMass(3) - Tip-brake mass, blade 3 (kg) [unused for 2 blades]
56780 HubMass - Hub mass (kg)
115926 HubIner - Hub inertia about rotor axis [3 blades] or teeter axis [2 blades] (kg m^2)
534.116 GenIner - Generator inertia about HSS (kg m^2)
240000 NacMass - Nacelle mass (kg)
2.60789E+06 NacYIner - Nacelle inertia about yaw axis (kg m^2)
0 YawBrMass - Yaw bearing mass (kg)
0 PtfmMass - Platform mass (kg)
0 PtfmRIner - Platform inertia for roll tilt rotation about the platform CM (kg m^2)
0 PtfmPIner - Platform inertia for pitch tilt rotation about the platform CM (kg m^2)
0 PtfmYIner - Platform inertia for yaw rotation about the platform CM (kg m^2)
---------------------- BLADE ---------------------------------------------------
17 BldNodes - Number of blade nodes (per blade) used for analysis (-)
“NRELOffshrBsline5MW_Blade.dat” BldFile(1) - Name of file containing properties for blade 1 (quoted string)
“NRELOffshrBsline5MW_Blade.dat” BldFile(2) - Name of file containing properties for blade 2 (quoted string)
“NRELOffshrBsline5MW_Blade.dat” BldFile(3) - Name of file containing properties for blade 3 (quoted string) [unused for 2 blades]
---------------------- ROTOR-TEETER --------------------------------------------
0 TeetMod - Rotor-teeter spring/damper model {0: none, 1: standard, 2: user-defined from routine UserTeet} (switch) [unused for 3 blades]
0 TeetDmpP - Rotor-teeter damper position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetDmp - Rotor-teeter damping constant (N-m/(rad/s)) [used only for 2 blades and when TeetMod=1]
0 TeetCDmp - Rotor-teeter rate-independent Coulomb-damping moment (N-m) [used only for 2 blades and when TeetMod=1]
0 TeetSStP - Rotor-teeter soft-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetHStP - Rotor-teeter hard-stop position (degrees) [used only for 2 blades and when TeetMod=1]
0 TeetSSSp - Rotor-teeter soft-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1]
0 TeetHSSp - Rotor-teeter hard-stop linear-spring constant (N-m/rad) [used only for 2 blades and when TeetMod=1]
---------------------- DRIVETRAIN ----------------------------------------------
100 GBoxEff - Gearbox efficiency (%)
97 GBRatio - Gearbox ratio (-)
8.67637E+08 DTTorSpr - Drivetrain torsional spring (N-m/rad)
6.215E+06 DTTorDmp - Drivetrain torsional damper (N-m/(rad/s))
---------------------- FURLING -------------------------------------------------
False Furling - Read in additional model properties for furling turbine (flag) [must currently be FALSE)
“unused” FurlFile - Name of file containing furling properties (quoted string) [unused when Furling=False]
---------------------- TOWER ---------------------------------------------------
20 TwrNodes - Number of tower nodes used for analysis (-)
“NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat” TwrFile - Name of file containing tower properties (quoted string)
---------------------- OUTPUT --------------------------------------------------
True SumPrint - Print summary data to “.sum” (flag)
1 OutFile - Switch to determine where output will be placed: {1: in module output file only; 2: in glue code output file only; 3: both} (currently unused)
True TabDelim - Use tab delimiters in text tabular output file? (flag) (currently unused)
“ES10.3E2” OutFmt - Format used for text tabular output (except time). Resulting field should be 10 characters. (quoted string) (currently unused)
0 TStart - Time to begin tabular output (s) (currently unused)
1 DecFact - Decimation factor for tabular output {1: output every time step} (-) (currently unused)
0 NTwGages - Number of tower nodes that have strain gages for output [0 to 9] (-)
10, 19, 28 TwrGagNd - List of tower nodes that have strain gages [1 to TwrNodes] (-) [unused if NTwGages=0]
3 NBlGages - Number of blade nodes that have strain gages for output [0 to 9] (-)
5, 9, 13 BldGagNd - List of blade nodes that have strain gages [1 to BldNodes] (-) [unused if NBlGages=0]
OutList - The next line(s) contains a list of output parameters. See OutListParameters.xlsx for a listing of available output channels, (-)

Thanks
Best regards

[Jason.Jonkman]

Dear NingXiang.Gao,

I’m not sure I really understand your question, but you appear to be asking what causes the sinusoidal variation in blade deflection. This could be the result of:

• Gravity loading, in combination with rotor rotation. The shaft tilt and tower deflection will cause some of the gravity load to impact out of plane deflection, in addition to in plane deflection.
• Shear and yaw error, in combination with rotor rotation. You haven’t stated what type of wind you’ve defined, but wind direction (yaw error, skewed flow) and shear will also lead to oscillating blade deflection.

Best regards,

[NingXiang.Gao]

Dear Jason,

I’m sorry for not clearly describing my question. I would like to know, with your experience, what is the reason for the circled part of the picture？I don’t understand the difference between my waveform and the waveform in Figure 2.I would like to get a smooth sinusoidal waveform like that shown in Figure 2.

And this is my wind input file

------- InflowWind v3.01.* INPUT FILE -------------------------------------------------------------------------
12 m/s turbulent winds on 31x31 FF grid and tower for FAST CertTests #18, #19, #21, #22, #23, and #24

False Echo - Echo input data to .ech (flag)
3 WindType - switch for wind file type (1=steady; 2=uniform; 3=binary TurbSim FF; 4=binary Bladed-style FF; 5=HAWC format; 6=User defined)
0 PropagationDir - Direction of wind propagation (meteoroligical rotation from aligned with X (positive rotates towards -Y) – degrees)
1 NWindVel - Number of points to output the wind velocity (0 to 9)
0 WindVxiList - List of coordinates in the inertial X direction (m)
0 WindVyiList - List of coordinates in the inertial Y direction (m)
90 WindVziList - List of coordinates in the inertial Z direction (m)
================== Parameters for Steady Wind Conditions [used only for WindType = 1] =========================
0 HWindSpeed - Horizontal windspeed (m/s)
90 RefHt - Reference height for horizontal wind speed (m)
0.2 PLexp - Power law exponent (-)
================== Parameters for Uniform wind file [used only for WindType = 2] ============================
“Wind/90m_12mps_twr.bts” Filename - Filename of time series data for uniform wind field. (-)
90 RefHt - Reference height for horizontal wind speed (m)
125.88 RefLength - Reference length for linear horizontal and vertical sheer (-)
================== Parameters for Binary TurbSim Full-Field files [used only for WindType = 3] ==============
“Wind/90m_12mps_twr.bts” Filename - Name of the Full field wind file to use (.bts)
================== Parameters for Binary Bladed-style Full-Field files [used only for WindType = 4] =========
“Wind/90m_12mps_twr” FilenameRoot - Rootname of the full-field wind file to use (.wnd, .sum)
False TowerFile - Have tower file (.twr) (flag)
================== Parameters for HAWC-format binary files [Only used with WindType = 5] =====================
“wasp\Output\basic_5u.bin” FileName_u - name of the file containing the u-component fluctuating wind (.bin)
“wasp\Output\basic_5v.bin” FileName_v - name of the file containing the v-component fluctuating wind (.bin)
“wasp\Output\basic_5w.bin” FileName_w - name of the file containing the w-component fluctuating wind (.bin)
64 nx - number of grids in the x direction (in the 3 files above) (-)
32 ny - number of grids in the y direction (in the 3 files above) (-)
32 nz - number of grids in the z direction (in the 3 files above) (-)
16 dx - distance (in meters) between points in the x direction (m)
3 dy - distance (in meters) between points in the y direction (m)
3 dz - distance (in meters) between points in the z direction (m)
90 RefHt - reference height; the height (in meters) of the vertical center of the grid (m)
------------- Scaling parameters for turbulence ---------------------------------------------------------
1 ScaleMethod - Turbulence scaling method [0 = none, 1 = direct scaling, 2 = calculate scaling factor based on a desired standard deviation]
1 SFx - Turbulence scaling factor for the x direction (-) [ScaleMethod=1]
1 SFy - Turbulence scaling factor for the y direction (-) [ScaleMethod=1]
1 SFz - Turbulence scaling factor for the z direction (-) [ScaleMethod=1]
12 SigmaFx - Turbulence standard deviation to calculate scaling from in x direction (m/s) [ScaleMethod=2]
8 SigmaFy - Turbulence standard deviation to calculate scaling from in y direction (m/s) [ScaleMethod=2]
2 SigmaFz - Turbulence standard deviation to calculate scaling from in z direction (m/s) [ScaleMethod=2]
------------- Mean wind profile parameters (added to HAWC-format files) ---------------------------------
5 URef - Mean u-component wind speed at the reference height (m/s)
2 WindProfile - Wind profile type (0=constant;1=logarithmic,2=power law)
0.2 PLExp - Power law exponent (-) (used for PL wind profile type only)
0.03 Z0 - Surface roughness length (m) (used for LG wind profile type only)
====================== OUTPUT ==================================================

TurbSim Input File. Valid for TurbSim v1.50; 17-May-2010; Example file that can be used with simulations for the NREL 5MW Baseline Turbine; note that UsableTime has been decreased in this file so that the file distributed with the FAST CertTest isn’t as large

---------Runtime Options-----------------------------------
13428 RandSeed1 - First random seed (-2147483648 to 2147483647)
RanLux RandSeed2 - Second random seed (-2147483648 to 2147483647) for intrinsic pRNG, or an alternative pRNG: “RanLux” or “RNSNLW”
False WrBHHTP - Output hub-height turbulence parameters in binary form? (Generates RootName.bin)
False WrFHHTP - Output hub-height turbulence parameters in formatted form? (Generates RootName.dat)
False WrADHH - Output hub-height time-series data in AeroDyn form? (Generates RootName.hh)
True WrADFF - Output full-field time-series data in TurbSim/AeroDyn form? (Generates RootName.bts)
False WrBLFF - Output full-field time-series data in BLADED/AeroDyn form? (Generates RootName.wnd)
True WrADTWR - Output tower time-series data? (Generates RootName.twr)
False WrFMTFF - Output full-field time-series data in formatted (readable) form? (Generates RootName.u, RootName.v, RootName.w)
False WrACT - Output coherent turbulence time steps in AeroDyn form? (Generates RootName.cts)
True Clockwise - Clockwise rotation looking downwind? (used only for full-field binary files - not necessary for AeroDyn)
0 ScaleIEC - Scale IEC turbulence models to exact target standard deviation? [0=no additional scaling; 1=use hub scale uniformly; 2=use individual scales]

--------Turbine/Model Specifications-----------------------
31 NumGrid_Z - Vertical grid-point matrix dimension
31 NumGrid_Y - Horizontal grid-point matrix dimension
0.05 TimeStep - Time step [seconds]
630.0 AnalysisTime - Length of analysis time series [seconds]
630.0 UsableTime - Usable length of output time series [seconds] (program will add GridWidth/MeanHHWS seconds) [bjj: was 630]
90.0 HubHt - Hub height [m] (should be > 0.5GridHeight)
155.0 GridHeight - Grid height [m]
155.0 GridWidth - Grid width [m] (should be >= 2(RotorRadius+ShaftLength))
0 VFlowAng - Vertical mean flow (uptilt) angle [degrees]
0 HFlowAng - Horizontal mean flow (skew) angle [degrees]

--------Meteorological Boundary Conditions-------------------
IECKAI TurbModel - Turbulence model (“IECKAI”=Kaimal, “IECVKM”=von Karman, “GP_LLJ”, “NWTCUP”, “SMOOTH”, “WF_UPW”, “WF_07D”, “WF_14D”, or “NONE”)
“1-ed3” IECstandard - Number of IEC 61400-x standard (x=1,2, or 3 with optional 61400-1 edition number (i.e. “1-Ed2”) )
“B” IECturbc - IEC turbulence characteristic (“A”, “B”, “C” or the turbulence intensity in percent) (“KHTEST” option with NWTCUP, not used for other models)
NTM IEC_WindType - IEC turbulence type (“NTM”=normal, “xETM”=extreme turbulence, “xEWM1”=extreme 1-year wind, “xEWM50”=extreme 50-year wind, where x=wind turbine class 1, 2, or 3)
default ETMc - IEC Extreme turbulence model “c” parameter [m/s]
PL WindProfileType - Wind profile type (“JET”=Low-level jet,“LOG”=Logarithmic,“PL”=Power law, or “default”, or “USR”=User-defined)
90. RefHt - Height of the reference wind speed [m]
12.0 URef - Mean (total) wind speed at the reference height [m/s]
default ZJetMax - Jet height [m] (used only for JET wind profile, valid 70-490 m)
default PLExp - Power law exponent [-] (or “default”)
default Z0 - Surface roughness length [m] (or “default”)

--------Non-IEC Meteorological Boundary Conditions------------
default Latitude - Site latitude [degrees] (or “default”)
0.05 RICH_NO - Gradient Richardson number
default UStar - Friction or shear velocity [m/s] (or “default”)
default ZI - Mixing layer depth [m] (or “default”)
default PC_UW - Hub mean u’w’ Reynolds stress [(m/s)^2] (or “default”)
default PC_UV - Hub mean u’v’ Reynolds stress [(m/s)^2] (or “default”)
default PC_VW - Hub mean v’w’ Reynolds stress [(m/s)^2] (or “default”)
default IncDec1 - u-component coherence parameters (e.g. “10.0 0.3e-3” in quotes) (or “default”)
default IncDec2 - v-component coherence parameters (e.g. “10.0 0.3e-3” in quotes) (or “default”)
default IncDec3 - w-component coherence parameters (e.g. “10.0 0.3e-3” in quotes) (or “default”)
default CohExp - Coherence exponent (or “default”)

--------Coherent Turbulence Scaling Parameters-------------------
“M:\coh_events\eventdata” CTEventPath - Name of the path where event data files are located
“Random” CTEventFile - Type of event files (“random”, “les” or “dns”)
true Randomize - Randomize disturbance scale and location? (true/false)
1.0 DistScl - Disturbance scale (ratio of dataset height to rotor disk).
0.5 CTLy - Fractional location of tower centerline from right (looking downwind) to left side of the dataset.
0.5 CTLz - Fractional location of hub height from the bottom of the dataset.
10.0 CTStartTime - Minimum start time for coherent structures in RootName.cts [seconds]

Thanks
Best regards

[Jason.Jonkman]

Dear NingXiang.Gao,

Well, the additional high-frequency oscillations can be caused by nonlinearities, turbulent excitation, e.g., harmonic effects (2P, 3P, 4P, etc.), or blade natural frequencies. I would recommend computing the power-spectral density (PSD) of the time series and identify at which frequency these oscillations occur.

Best regards,

[NingXiang.Gao]

Dear Jason,

Can FAST output aerodynamic loads on three blades respectively? I only found RtAeroFxh, RtAeroFyh, RtAeroFzh in OutListParameters, but that’s not the output I wanted.

There’s another question，when I output B1N1Fx, B1N2Fx… B1N9Fy, it’s all zero,what could cause this problem?

Thanks,
Best regards,

[Jason.Jonkman]

Dear NingXiang.Gao,

Are you asking about the total aerodynamic loads applied to the entire blade? These are not outputs of AeroDyn v15, without customization of the source code.

Regarding the outputs B1N1Fx etc., if these are all zero, my guess is that you haven’t defined the blade output nodes via the input parameters NBlOuts and BlOutNd in the AeroDyn v15 primary input file.

Best regards,